Patent GB-663259-A (GB)
Title: Improvements in valve systems for reciprocating motors
IPC: F01L21/04
Filed: 1949-12-24
Abstract: 663,259. Gaseous-pressure engines; engine valve gear. MARPLES & SON, Ltd., R. M., and MARPLES, D. D. Dec. 24, 1949, No. 33054/49. Classes 122(ii) and 122(iii) [Also in Group XXIX] In a gaseous-pressure reciprocating engine an annular section valve sleeve is interposed between the piston and piston rod and has limited sliding movement relative thereto and the admission and exhaust from each end of the cylinder is initiated and controlled by the movement of the valve sleeve from one limiting position to the other and by co-operation of ports in the valve sleeve with ducts in the piston and piston rod which communicate with the cylinder ends, with the pressure gas and with exhaust. A piston 3, having an internal liner 4 reciprocates in a cylinder 2 and is attached to a piston rod 6 by two driving pins 5, 5a which pass through slots 28 in,an annular valve sleeve 7, interposed between the piston and piston rod, so that the valve sleeve is capable of limited sliding movement but rotationally fixed relative to the piston and piston rod. The latter has therein a pressure gas longitudinal duct a and an exhaust longitudinal duct h stopping just short of pins 5 and 5a respectively and having transversely grilled at their inner ends opposite circular ducts permanently aligned with similar ducts c, k, and 1, f, r,espectively in the piston. The ducts c, l interpenetrate a longitudinal duct d<SP>1</SP> in the piston which communicates through a duct d with one end s<SP>1</SP> of the cylinder and the ducts k, f interpenetrate a similar duct e<SP>1</SP> communicating through a duct e with the other end S<SP>2</SP> of the cylinder. The sleeve valve 7 is of greater axial length than the piston 3 and has circular ports b, j, i and g in a common plane transverse to the plane containing the pins 5, 5a. Helical springs 15, 16 surrounding reduced portions of the piston rod bearings 11, 12 are housed in recesses in the cylinder ends 8, 9 and, under no load conditions, project into the cylinder. In the position shown pressure gas passes through ducts a, c, d and port b into the cylinder space s' whilst the other end s<SP>2</SP> of the cylinder is open to exhaust through ducts e, f, h and port g, and the piston moves to the right and continues to move past the point in the stroke when the end of the valve sleeve 7 abuts and starts to compress the spring 16 until the compressive force in the spring moves the sleeve relative to the piston rod to its other limiting position and the ports i and j are moved into alignment with the ducts k and l respectively thereby putting the cylinder space s<SP>1</SP> to exhaust through ducts a, k, e<SP>1</SP>, e and port i and supplying pressure gas to cylinder space s<SP>2</SP> through ducts a, k, e<SP>1</SP>, e and port j and thus reversing the piston which moves to the left until the force due to the compression of the spring 15 by the end of the valve sleeve 7 restores the latter to its original position and the cycle recommences. The system of ducts in the piston rod, piston and valve sleeve may be duplicated and additional piston rods, which may or may not, perform the functions of the valve mechanism, may be provided. In a modification the piston and piston rod are stationary and the cylinder reciprocates.